Given the height of the wind turbines and their erection in elevated regions lacking other elements having similar heights, there is a high risk of being struck by lightning, especially in the blades. With this in mind, blades must be equipped with a lightning protection system, and any other additional system installed in the blade containing conductor elements (metal parts, sensors, beacon systems, etc.) must be protected against direct impacts of lightning bolts and indirect effects of the electromagnetic field induced by the bolt current.
The primary components of the lightning protection system for wind turbine blades are a series of metal receptors mounted on the surface of the blade and a cable conductor to transit the bolt from the receptors to the blade root.
The evolution of wind turbines together with the growth in their provided power have led to new generations of wind turbines having ever-increasing dimensions insofar as tower height and rotor diameter. Blade lengthening necessitates an increase in rigidity. The use of a larger quantity of carbon fiber-based laminates in blade production is common to achieve this rigidity. However, carbon fiber laminates are conductors and must therefore be connected in parallel with the lightning protection system conductor cable to prevent internal arcing between the cable and the laminates and direct lightning bolt strikes on the carbon laminate.
In this regard, international patent WO2006051147, which presents a “lightning conductor system for wind generator blades comprising carbon fibre laminates”, can be cited since the use of carbon fiber in blade beam construction requires that this material be equipotentialized with the lightning conductor system. To do so, the primary cable of the lightning conductor system is furnished with bypasses for connections directly with the carbon fiber laminates. These auxiliary cables are connected with a bolted joint to a metal plate in direct contact with the carbon fiber layers. The electrical connection can be improved with the use of additional conductor resins in the joint area.
Notwithstanding this solution, the distribution of current transmitted across the cable and carbon laminates are not controlled, which could make the transfer of current across the carbon without damaging it even more difficult, thus necessitating a device to connect the carbon fiber laminates in parallel with the cable conductor of the system and to control the current circulating through the carbon fiber as in the proposal for the present invention.